Acne is the most common skin condition that affects ~ 85% of the adolescent population in the United States and accounts for expenditure of billions of health care dollars annually. In this era of change in the economy and change in health care practice patterns, there is an increasing need for practitioners to make evidence-based decisions regarding acne treatment. Although large numbers of clinical trials have been conducted for the hundreds of available acne medications, there is very little data available by which one treatment can be compared to another. Resources to conduct large clinical trials to compare acne therapies are limited. Moving forward, it is more likely that comparative effectiveness research in the area of acne will rely upon secondary analysis of clinical trial data sets. Progress in this area has been greatly hampered by the lack of standardized outcomes measures in acne clinical trials that allows comparison across studies. Following the model of the OMERACT group in rheumatology, an international multi-stakeholder group of experts in evaluation of acne, care of acne patients with diverse skin phototypes, social psychology, analysis of data from acne trials, regulatory affairs, measurement of patient reported outcomes and patient representatives have been assembled and named Acne Core Outcomes Research Network (ACORN). A scientific advisory board of experts will be appointed to provide direction to ACORN initiatives. The approach will be to accomplish a series of short-term objectives that will serve as resources in acne evaluation while pursing the long-term goal to develop a tool box of validated outcome measures for use in acne clinical trials. At present, acne lesion counts and investigator global assessment of acne severity are the 2 major outcomes measured in regulatory trials. In addition, there is a lack of patient-reported outcomes measures of truncal acne that affects ~ half of all acne patients. Short-term objectives include: 1). Development of a web- based standardized instrument for lesion counting in acne (SILCA) to improve the variability associated with acne lesion counting; 2). Development of a comprehensive instrument to assess the impact of truncal acne on patient's quality of life (CompAQ); and 3). Generation of pilot data on a series of 4 novel technologies to assess acne and/or train acne evaluators. Progress towards our long-term objective will include, reaching consensus on outcome domains and desired features of outcome measures, completion of systematic reviews of acne outcome measures of acne severity and its impact, assessment of reliability and feasibility of select global assessment scales and preliminary development of a new or revised global severity scale(s). A team-based strategy will be used to simultaneously pursue the project aims. Each team has designated primary responsibility for portions of the project. Teams are based in the US (Drs. Thiboutot/Chren); the UK (Drs.Layton/Eady) and Canada (Drs.Tan/Wolfe). Global communication strategies will supplement face-to-face meetings and Six Sigma principles of project management will be employed.